Method of protecting pipe seams and joints



C. V. WITT METHOD OF PROTEGTING PIPE SEAMS AND JOINTS Aug. 5, 1930.

Filed oct, 5, 1929 !ITEMFM INVENTOR WITNESS rica CHARLES V'. WITT, 0F GREENSBURG, PENNSYLVANIA METHOD DFPROTECTING PIPE SEAIVIS AND J'ONTS i Application filed October 5, 1929. Serial No. 397,573.

This invention relates to protection of the are, from the standpoint of corrosion resistexterior surface of pipes against corrosion, ance, the Weakest points of the pipe. Furand has particularly to do With the protection therm-ore, in the handling of the pipe the of pipes Whichfare so fabricated and con- Wrapping frequently becomes puiictured at nected to eachother that they have external the voids, permitting the ingress of Water protruding seams, as for example lock-bar between the Wrapping and thecoat-ing. and riveted seam pipes. The object of this invention is to provide To protect pipes against corrosion, it is a method of adequately protecting against common practiceto dip them in a large tank corrosion the seams protruding from thel exof properly heated corrosion-resisting materior of pipes' which are otherwise protected k6U terial, such as rened asphaltum, the pipe against corrosion in the manner explained usuallyV being preheated to about the temperabove. ature of the material before being dipped in In the practice of this invention, protrudit. After removing the pipe from the tank ing seams are protected against corrosion by the excess coating material is permitted to precasting strips of corrosion-resisting mate- 55 drain from it into receptacles `vvhich-necesrial in suchl forms that their interior faces sarily expose the materialy for such periods conform to theprotrusions of the seams, and of time that it becomes somewhatcontanii- `so applying s uch `stripsto the seams that nated With dust and other foreign matter, Vthe recesses of the former encase theV proand also loses some of its volatile constituents, trusions of the latter. The exterior sur- 70 OIl aCCOUnt 0f WlliClltlle drip material S OI'- faces of vthe strips are 0f Convex form7 S0 dinarily not returned to the dipping tank. shaped that, inthe case of longitudinal seams,

The dip coating thusapplied lis rather thin, they merge into the curvature of the pipes so and accordingly insufficient to adequately that helically applied Wrappings do not beresist corrosion, particularly under highly come spaced from the pipes, and, in the case 75 Vcorrosive conditions of service. To increase of girt seams, either helical or annular strips the corrosion resistanceofsuch dipped'pipe, of flexible material applied to thejpipe and the practice is to encase it in avhelical oveistrips readily conform yto them. lapping Wrapping of iiexible strips of paper While various corrosion-resisting mateor cloth, such as'felt, While pOUTIlg heflted rials may be used for forming the strips, they 80 asphaltum or other corrosion-resisting mateare preferably cast from heated asphaltum, rial between the pipe and the Wrapping as the it being possible to use thepartially containpipe is rotated to apply the Wrapping. There inated material which drips from the dipis thus provided a much heavier coating of coated pipe because it is unnecessary to use corrosion-resisting material, which, until it material of the highest purity for casting 85 solidities, is held uponthe-pipe by the helical the strips. Before applying the strips to- 'Wrappingz longitudinal scams, a liquid coating of corro- In thus applying an extra. coating of corsion-resistinggj material, preferably heated asrosion resisting materialto the pipe, it has phaltum, is applied to the seams and tothe 40 not been possible to satisfactorily prevent the adjacent surfaces of the strips for sealing 90 presence of voids between the Wrapping' and the strips to the pipes. Also, before applythe pipe at the protruding seams of the lating the strips to the seams, the former are ter. The riveted or lock-bar seams so prosufficiently heated to permit them to be bent trude from the exterior cylindrical surfaces to the curvature of the pipe as they are apof the pipes that the protrusions raise the plied to the seaiii l 95 Wrapping from the adjacent surface portions rlhe invention may be further .explained ofi-the pipes, and the spaces between the thus with reference to the accompanying drawraised Wrapping and the pipedo not become ings, of which Fig. l is an elevation of a seclled With the coating material. Accordtion of pipe having riveted longitudinal and ingly, both 4the longitudinal and girt seams girt seams, a portion of the pipe being shown 100 as having a wrapping of flexible material helically applied to it; Fig. 2 a transverse sectional view taken on the line lI-ll, Fig. l, diagrainmatically illustrating tl e manner of applying` the helical Wrapping of the pip-e; Fig. 3 a detail ectional viev.r taken on the line IIL-lll, Fig. l, illustrating` to enlarged scale a longitudinal riveted seam with a precast strip of corrosion-resisti material applied to it; Fig. i a face vienv of a portion of a precast strip g and Fig. 5 a sectional vieiv of a suitable mold for casting the strips.

The section of pipe illustrated in Fig. l is formed from four plates l, 2, and a, each of which is bent to cylindrical forni with its overlapping edges joined together bya longitudinal riveted seam, such as illustrated at 5 in Figs. l and 2, the ends of adjacent portions telescoping with each otherand connected by riveted girt seams. To cach longitudinal seam there is applied a precast strip G which has been suliiciently heated to permit it to be readily bent to conform, to the curved surface of the pipe. As shown in Fig. 3, the strip has its interior surface provided With recesses conforming to the exterior rivet heads of the seams and to the step between the overlapping edges of the plate. As also appears from Fig. 3, the exterior surface of strip 6 is formed to merge with the curvature of the pipe, or in other Words is so curved that it merges tangentially with the curvature of the pipe so that `When a Wrapping is applied there are no voids between it and the pipeand strip. Lilewise, suitable precast strips 8 are applied to the girt seams of the pipe, these strips having interior surfaces which conform to the protrusions at the girt seams, and having exterior surfaces which permit the Wrapping to be applied Without forming voids. At its end, each longitudinal strip 6 may be suitably tapered to extend into a notch cut in theside of a. girt strip 8, as shown at 9, so that the tivo properly inerge into each other.

trips 6 may be cast in a mold, such as shown in Fig. 5, comprising a bottoni l0 and a top plate l1, the lower surface of which plate is provided with rivet heads 12 for forming recesses in theA strip located and spaced the saine as the heads of rivets at the seam. The tliicl-:uess of plate ll is the same as that of the plate of Which the pipe is formed so that the edge 13 of plate ll forms a stop in the strip conforming to the overlapping edge of the plate at its seam. The inold cavity thus formed is filled With a body of heated asplialtuin, or other suitable corrosion-resistingn material, to the level of the upper face or' the plate 11. after the strip has set sutliciently for handling, it may be removed from the mold by iii-st removing plate l1 which may be attached to-mold bottom rl0 by bolts la. ln Fig. l there is illustrated the recess provided for the face of strip 6 to be applied to the longitudinal seams of the pipe shown in Fig. l, the strip being shown as being provided with staggered rivet head recesses and with a stepped oiiset. ln a similar manner other strips for seams having different protrusioiis may be precast in suitably formed molds.

In applying the strips to a section of pipe in a fabricating plant, the strips are lirst heated suiiiciently to pcrniit them to conform to the curvature of the pipe, and then placed on the pipe with an interposed coating of sealing material. Thereafter the pipe is Wrapped with a strip of flexible material, the pipe being' rotated as the strip is helically applied to it. lvlhile the Wrapping is applied, heated corrosion-resisting material is rplaced between the strip and the pipe, Which may be done by pouring the material as diagrammaticaliy illustrated in Fig. 2. rThe Vgirt joints in the field may be protected by precast strips in substantially the same manner. as explained, a layer of flexible material being aniiularly applied to the girt oint strips after they are applied to the pipe joints.

Although the invention has been illustrated and described primarily with reference to the protection of riveted seained pipe, it will be understood that it is applicable to lock-bar and other forms of pipe which have protruding seams, it being only necessary to precast the protecting strips in such forms as to conform to the various shapes of protruding seams'and to prevent the presence of voids between the Wrapping and the coating.

I claim as my invention:

l. The method of protecting` against corrosion a seam protruding from the exterior of a pipe, comprising precast-,ing a strip .of corrosion-resisting material with a face having recesses conforming` to the protrusions of the saine, and applying said strip to the pipe seam with the recessof the former encasing the protrusions of the latter. y

2. Theinethod of protecting against corrosion a seam protruding from the exterior of a pipe, comprising pi-ecasting a strip of corrosion-resisting material with a face having recesses conforming to the protrusions ofthe seam, applying said stripto the pipe seam With the recesses of the former encasing the protrusions of the latter, and encasing said strip and pipein a wrapping of flexible material.

3. -The method of protecting against corrosion a longitudinal seam projecting from the exterior of a pipe, comprising precasting a strip of.corrosion-resisting material with its interior face having` recesses conforming to the protrusions of the seam and With its exterior convex surface formed to merge into that'of pipe to which the strip is applied, applying said strip to the pipe seam with the recesses of the former eneasing the protrusions of the latter, and encasing the pipe and strip in a Wrapping of flexible material helically applied to the pipe.

4. The method of protecting against corrosion a longitudinal seam projecting from the exterior of a pipe, comprising preoasting a strip of Corrosion-resisting material With its interior face having recesses Conforming to the protrusons of the seam and with its exterior convex surface formed to merge into that of pipe to Which the strip is applied, sealing said strip to the pipe seam by a Huid coating of Corrosion-resisting material and with the recesses of the strip enoasing the protrusions of the seam, and eneasing the pipe and seam in a Wrapping offlexible Inaterial helically applied to the pipe.

In testimony whereof, I sign my name.

CHARLES V. WITT 

